Python tests misconfiguration for gc-check target

[kurapov-peter]

Running gc checks directly after a clean build fails on python tests due to some misconfiguration.

compile.sh --dev
cmake --build build/ --target gc-check

E.g.,

RUN: at line 4: "/usr/bin/python3.10" /localdisk/pakurapo/graph-compiler/test/mlir/test/gc/python/dialects/cpuruntime.py | /localdisk/pakurapo/graph-compiler/externals/llvm-project/build/bin/FileCheck /localdisk/pakurapo/graph-compiler/test/mlir/test/gc/python/dialects/cpuruntime.py
+ /usr/bin/python3.10 /localdisk/pakurapo/graph-compiler/test/mlir/test/gc/python/dialects/cpuruntime.py
+ /localdisk/pakurapo/graph-compiler/externals/llvm-project/build/bin/FileCheck /localdisk/pakurapo/graph-compiler/test/mlir/test/gc/python/dialects/cpuruntime.py
Traceback (most recent call last):
  File "/localdisk/pakurapo/graph-compiler/test/mlir/test/gc/python/dialects/cpuruntime.py", line 6, in <module>
    from gc_mlir.dialects import cpuruntime, func
  File "/localdisk/pakurapo/graph-compiler/build/python_packages/gc_mlir_core/gc_mlir/dialects/cpuruntime.py", line 10, in <module>
    from .._mlir_libs._gc_mlir.cpuruntime import *
ImportError: /localdisk/pakurapo/graph-compiler/build/python_packages/gc_mlir_core/gc_mlir/_mlir_libs/_gc_mlir.cpython-310-x86_64-linux-gnu.so: undefined symbol: _ZNK4llvm5Twine3strB5cxx11Ev
FileCheck error: '<stdin>' is empty.